Spinal Stenosis

In order to understand this topic it is important to understand the basic anatomy of the spine. Please review the section on basic spine anatomy before reading this section. To understand how the spine works, please review the section on the basic spine biomechanics.

Lumbar Spinal Stenosis
Lumbar Spinal Stenosis

What is spinal stenosis?

Stenosis is a medical term for narrowing. Spinal stenosis is defined as any narrowing of the central and/or lateral canals of the spine.

What are the central and lateral canals of the spine?

Each back bone (vertebra) has a hole in the centre and when stacked on top of each other they form a hollow tube (central canal). This tube or canal holds and protects the entire spinal cord and its nerve roots. The spinal cord is a large bundle of nerve fibers that transmit messages from the brain to the rest of the body; allowing for motor movement and sensory perception. There are nerves that branch off from the spinal cord and exit the spinal column between each back bone. This exit area for nerves is known as the lateral canal, and these canals exist on both right and left sides to transmit messages to both right and left sides of the body.

What does spinal stenosis feel like?

When the lateral and/or central canals are narrowed the following symptoms are observed: dull to severe aching type pain in the low back or buttocks when walking or with prolonged standing. There may also be pain, numbness and/or weakness that radiates (spreads) into one or both thighs and legs. Symptoms are relieved by bending forward, sitting or lying down.

What causes spinal stenosis?

Normally extra space exists in the central and lateral canals allowing for normal spinal movement. However this space can be reduced by many conditions. If the space begins to narrow the risk of irritating or injuring the spinal cord or nerves increases. Some conditions that lead to narrowing of the spinal canal include: infection, tumours, trauma, herniated discs, arthritis, thickening of ligaments, growth of bone spurs, and disc degeneration. Stenosis can occur in all areas of the spine, but it is most common in the lumbar spine.

Spinal stenosis is more common problem in people over the age of 60. However it can occur in people younger than 60 years old that have developmentally smaller canals. In older people there is wear and tear or spinal degeneration on all the structures surrounding the spinal canals. This degeneration can cause various problems such as: thickening of the large ligaments that connect the back bones together, abnormal bony outgrowths around the back bone (facet) joints and disc space, and bulging of the discs themselves. All of these changes can narrow the canals and increase pressure on the sensitive nerves of the spine causing pain and nerve problems. Increased pressure can reduce the blood and oxygen supply to the spinal cord. With increased activity like walking the blood vessels may not be able to swell to get blood to the spine. A lack of blood and oxygen may lead to numbness and pain in the compressed nerves. Nerves can also become inflamed and irritated if their mobility is compromised when their space for movement is reduced.

How is spinal stenosis diagnosed?

Most cases of spinal stenosis are diagnosed through good medical history and a physical examination. A physician may order a variety of diagnostic tests; the most common are X-rays of the lower back which show bones but not much soft tissue. For soft tissue (ligament, disc, nerve) investigation an MRI or CT scan may be ordered.

How is spinal stenosis treated?

There are different degrees of spinal stenosis: mild, moderate and severe. Mild and moderate stenosis are usually treated conservatively (without surgery). Severe spinal stenosis can be treated with surgery depending on the patients’ symptoms and limitations.

Conservative treatment includes hands-on physical therapy (joint mobilization or manipulation), exercise that favours forward bending, and education on positioning, anti-inflammatory medications, pain medications and bracing. In some cases these treatments may not be effective and other options such as injections that block the pain messages from the nerves may be helpful. Doctors and Physical Therapists with experience treating spinal stenosis can help outline an individualized treatment program. Spinal surgery is a treatment option that is a joint decision made between you, your spine surgeon and your family physician. The main goal of the surgery is to relieve pressure on the nerve roots. This type of surgery is called decompression, and the canals are made bigger to relieve pressure. The spinal canals are made bigger by removing bone; this may lead to instability of the spine and often a fusion along with decompression of the nerves is performed.

What other information is available on spinal stenosis?

Back Pain Info / Neck Pain Info’s links section has additional information on this topic. Links have been provided to other websites as well as online medical journals. Visit Joint Pain Info. Com for information on other joint injuries and problems.